Decoder Question

Model Railroader General Discussion (Model Railroader)
1

First, hi Randy, Joe and Nigel (I suspect the title will draw them here!).

I am in the process of painting, re-wheeling and equipping a fleet of Life Like N-scale FA2s and FB2s. Since these are carbody units, the A’s have a single headlight and will get a rotary beacon installed. The B’s will have neither.

It seems like any decoder that will fit the B can work without regard for the number of functions. I was originally thinking the A’s needed 3-function decoders minimum (the two normally associated with headlights and one for the beacon). However, I overlooked the obvious - they have only one headlight. As I see it, both the headlight and beacon will be non-directional (by choice). The only requirement is that there be a beacon effect for the beacon. So, is there any case to be made for anything more than a 2-function decoder?

What has me confused is that the Digitrax decoder manual states that for single-headlight locos you tie the white and yellow leads together. If true, that means I need the third function (Green lead) for the beacon. But, unless I am missing something, this can all be established through two functions and CVs 49 and 50.

What this all boils down to is the choice between TCS M1/Digitrax DZ123 or TCS M3/Digitrax DZ143.

2

On the Digitrax decoders you can program F0F and F0R independently, or at least the decoder manual SAYS you can, I haven’t tried it. CV49 controls F0F, and CV50 controls F0R. You can program F0F to be non-directional so the light is on all the time, or just in the forward direction. You can also map it so F1 controls the F0R output by setting CV35 to 2.
I’m pretty sure you can do the same thing with the TCS decoders. I just have the Digitrax decoder manual handy but not the TCS one (it’s on their web site). Look for ‘function remapping’.

–Randy

3

Thanks Randy,

That was my take on it, too. TCS does work the same way, at least according to their manual. I downloaded their info this morning and just got a chance to look at it.